A great example of using a 3D printer to make something that makes things. It’s available on Thingyverse and coupled with a powerful vacuum you can make molds of anything you like. The creator says you can use it to make molds of 3D things you have printed. I suppose you could also just print the mold directly but then you don’t get a decent enough mold for making chocolate wonders.
The OTM-02 (Open source Time Machine – version 2) is an open source watch design in development. The 7mm watch module will be housed in a 3D printed case, an intermediate design of which is pictured above. The development is still in progress with the release of a 3D CAD data for a printable case planned for end of April 2013.